Selective service method in multicast system

ABSTRACT

A multicast service of a 3GPP Universal Mobile Telecommunications System (UMTS) is disclosed. A multicast service stream identifier is provided so that each multicast area can receive different information for one service or one multicast service can be provided with different QoSs to areas. In addition, the multicast service stream identifier is provided which can selectively receive diverse menus or channels for one multicast service provided in the same area. Thus, by providing the multicast service stream identifier, users&#39; desires for various services can be satisfied.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multicast service of a 3GPP UniversalMobile Telecommunications System (UMTS) and, more particularly, to aselective service method in a multicast system.

2. Description of the Background Art

A universal mobile telecommunications system (UMTS) is a thirdgeneration mobile communication system that has evolved from a standardknown as Global System for Mobile communications (GSM). This standard isa European standard which aims to provide an improved mobilecommunication service based on a GSM core network and wideband codedivision multiple access (W-CDMA) technology.

In December, 1998, the ETSI of Europe, the ARIB/TTC of Japan, the T1 ofthe United States, and the TTA of Korea formed a Third GenerationPartnership Project (3GPP) for the purpose of creating the specificationfor standardizing the UMTS.

The work toward standardizing the UMTS performed by the 3GPP hasresulted in the formation of five technical specification groups (TSG),each of which is directed to forming network elements having independentoperations.

More specifically, each TSG develops, approves and manages a standardspecification in a related region. Among them, a radio access network(RAN) group (TSG-RAN) develops a specification for the function, itemsdesired, and interface of a UMTS terrestrial radio access network(UTRAN), which is a new RAN for supporting a W-CDMA access technology inthe UMTS.

FIG. 1 illustrates an example of the construction of a general UMTSnetwork.

The UMTS is roughly divided into a terminal, a UTRAN and a core network.

The UTRAN includes one or more radio network sub-systems (RNS). Each RNSincludes an RNC and one or more Node Bs managed by the RNCs.

Node Bs are managed by the RNCs, receive information sent by thephysical layer of a terminal (e.g., mobile station, user equipmentand/or subscriber unit) through an uplink, and transmit data to aterminal through a downlink. Node Bs, thus, operate as access points ofthe UTRAN for terminal.

The RNCs perform functions which include assigning and managing radioresources, and operate as an access point with respect to the corenetwork.

The UTRAN constructs and maintains a radio access bearer (RAB) forcommunication between the terminal and the core network. The corenetwork requests end-to-end quality of service (QoS) requirements fromthe RAB, and the RAM supports the QoS requirements the core network hasset. Accordingly, by constructing and maintaining the RAB, the UTRAN cansatisfy the end-to-end QoS requirements.

The services provided to the specific terminal is roughly divided into acircuit switched service and a packet switched service. For example, ageneral voice phone call service belongs to the circuit switchedservice, while a Web browsing service through an Internet connection isclassified as the packet switched service.

In case of supporting the circuit switched service, the RNC is connectedto the MSC of the core network, and the MSC is connected to a GMSC(Gateway Mobile Switching Center) managing a connection to othernetworks.

Meanwhile, in case of the packet switched service, services are providedby a SGSN (Serving GPRS Support Node) and a GGSN (Gateway GPRS SupportNode) 37 of the core network.

The SGSN supports a packet communication going toward the RNC, and theGGSN 37 manages connection to other packet switched networks (i.e, theInternet network).

As the 3GPP system has decided to provide a multimedia broadcastmulticast service (MBMS), a fresh service of Release 6, 3GPP TSG SA(Service and System Aspect defines network elements required for theMBMS service and functions of each network element.

A cell broadcast service the conventional Release 99 has provided islimited to a service that a text type short message is broadcast to acertain area. Comparatively, the MBMS service provided by the Release 6is an advanced service that not only broadcasts a multimedia but alsomulticasts the multimedia to terminals (UEs) which have subscribed forthe corresponding service.

The MBMS will now be described in detail.

The MBMS, a downward-dedicated service, provides a streaming orbackground service to plural terminals by using a common or dedicateddownward channel. The MBMS is divided into a broadcast mode and amulticast mode. The MBMS broadcast mode is a service transmittingmultimedia data to every user located in a broadcast area, whereas theMBMS multicast mode is a service transmitting multimedia data to aspecific user group located in a multicast area. The broadcast areasignifies a broadcast service available area, and the multicast areasignifies a multicast service available area.

Users who desire to receive the MBMS service should receive a serviceannouncement and a service notification provided by a network. Theservice announcement means informing the terminal of a list of servicesto be provided and its related information, and the service notificationmeans informing the terminal of information on broadcast data to betransmitted.

Especially, if the user intends to receive the multicast mode MBMSservice, he/she should be admitted to a multicast subscription group.The multicast subscription group means a group of users who has finishedan admission procedure. Once the user is admitted to the multicastsubscription group, he/she can join a multicast group to receive aspecific multicast service. In this case, the multicast group signifiesa user group receiving the specific multicast service, and ‘joining’means joining the multicast group gathered to receive the specificmulticast service.

The joining behavior is in other way called a MBMS multicast activation.Accordingly, the user can receive the specific multicast data throughthe MBMS multicast activation or the joining behavior.

FIG. 2 shows a schematic network structure for providing the MBMSservice.

As shown in FIG. 2, a broadcast multicast-service center (BM-SC) servesto schedule MBMS contents inputted from a contents provider. A cellbroadcast center (CBC) is an entity (a physical or virtual unit handlinga specific service) for providing an existing CBC service, that is, forbroadcasting a text type short message to a certain area, and can beused for a service announcement of the MBMS service.

Meanwhile, in the case of the packet switched service, the MBMS serviceis provided by an SGSN (Serving GPRS Support Node) and a GGSN (GatewayGPRS Support Node) of the core network. The SGSN supports a packetcommunication toward a serving RNC (SRNC) of the UTRAN, and the GGSNmanages connection to other packet switched networks such as theInternet through a border gateway (BG).

In the UMTS system, a GTP (GPRS Tunneling Protocol) layer is used tosupport transmission of the packet data. Specifically, the GTP layer isespecially used for transmitting data of a service area. Thus, the GGSNmanages a data transmission tunnel through the GTP layer in the existingUMTS packet domain, and generates and manages an MBMS context for theMBMS service.

FIG. 3 illustrates a transmission procedure of an MBMS data.

As shown in FIG. 3, data to be transmitted to members of the multicastgroup is delivered from an MBMS data source to the GGSN through an IPmulticast, and the GGSN generates a GTP tunnel and transmits an MBMSdata to the SGSNs which manage users subscribed for the correspondingmulticast service through the GTP tunnel. Each SGSN routes the MBMS datato each RNC managing corresponding users, and the RNC transmits thereceived MBMS data to a corresponding user cell (the area managed by oneNode B).

Accordingly, the specific MBMS service user located in the cell, thatis, the specific terminals located in the corresponding multicast area,can be provided with the MBMS service upon receiving the MBMS data.

If the BM-SC includes the function of the GGSN, the MBMS data can bedirectly delivered to the SGSN without passing through the GGSN, and thedata would be transmitted to the other entities in the same manner.

As mentioned above, the MBMS service includes the broadcast mode serviceand the multicast mode service. Unlike the broadcast mode service whichbroadcasts to all the area, the multicast mode service transmits dataonly to the users (terminals) admitted to the multicast group, of whichthe data is provided in a unidirectional point-to-multipoint transportmethod.

With respect to providing the multicast service, demands that differentinformation by areas should be provided for one service or demands thatone service with different QoSs (Quality of Service) by areas should beprovided are increasing. In addition, there should exist a variety ofmenus or channels for one service provided in the same area.

However, currently, the 3GPP defines only the requirements for the MBMSservice, failing to provide a substantial method as to how to performthe requirements.

The above references are incorporated by reference herein whereappropriate for appropriate teachings of additional or alternativedetails, features and/or technical background.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a selectiveservice method of a multicast system that is capable of transmittingdifferent MBMS service data by multicast groups.

Another object of the present invention is to provide a selectiveservice method of a multicast system that is capable of transmitting thesame MBMS service data but with different QoSs by multicast groups.

Still another object of the present invention is to provide a selectiveservice method of a multicast system that is capable of providingdiverse menus or channels for one multicast service.

To achieve at least the above objects in whole or in parts, there isprovided a selective service method of a multicast system in a systemproviding a multimedia broadcast/multicast service (MBMS), including:attaching an identifier (ID) for a multicast service to an MBMS data;and multicasting the identifier-attached MBMS data stream.

Preferably, the identifier includes: an MBMS service ID and an IDindicative of a kind of a lower service of the MBMS service. In such acase, the MBMS service ID consists of an access point number (APN) andan IP multicast address.

Preferably, the ID indicative of a kind of a lower service is amulticast group ID.

Preferably, the ID indicative of a kind of a lower service includes amulticast group ID and a multicast area ID.

Preferably, the ID indicative of a kind of a lower service includes amulticast group ID, a multicast area ID and an UDP/TCP port number.

To achieve at least these advantages in whole or in parts, there isfurther provided a selective service method of a multicast system in asystem providing a multimedia broadcast/multicast service (MBMS),including: attaching a first identifier (ID) for an MBMS data multicastservice; attaching a second identifier indicative of a kind of a lowerservice of an MBMS data; and multicasting the MBMS data stream with thefirst and second identifier attached thereto.

Preferably, the first identifier is an MBMS service ID.

Preferably, the MBMS service ID consists of an access point number (APN)and an IP multicast address.

Preferably, the second identifier is a multicast group ID.

Preferably, the second identifier includes a multicast group ID and amulticast area ID.

Preferably, the second identifier includes: a multicast group ID; amulticast area ID; and an UDP/TCP port number.

To achieve at least these advantages in whole or in parts, there isfurther provided a selective service method of a multicast system in asystem providing a multimedia broadcast/multicast service (MBMS),including: classifying an entire multicast service area into certainunits; attaching an identifier of the classified area to a multicastdata stream; and multicasting the identifier-attached multicast datastream.

Preferably, the entire multicast area is classified by multicast groups,by multicast areas and by multicast services. In such a case, theidentifier is performed by a member managing entity of a core networkwhich can be one of a Broadcast Multicast-Service Center (BM-SC), aServing GPRS Support Node (SGSN) and a Gate GPRS (GGSN).

Preferably, the identifier is an MBMS service IDA and a multicast groupID.

Preferably, the MBMS service ID consists of an access point number (APN)and an IP multicast address.

Preferably, the identifier includes: an MBMS service ID; a multicastgroup ID; and a multicast area ID.

The selective service method of a multicast system further includes:attaching another identifier indicative of a kind of a lower service tothe multicast data stream.

Preferably, the identifier indicative of a kind of a lower service is anUDP/TCP port number.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objects and advantages of the invention may be realizedand attained as particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

FIG. 1 illustrates a network structure of a general UMTS system;

FIG. 2 illustrates a schematic network structure for providing an MBMSservice in an UMTS system;

FIG. 3 illustrates a transmission path of an MBMS service data in theUMTS system;

FIG. 4 is a flow chart of a selective service method of a multicastsystem in accordance with the present invention;

FIG. 5 illustrates a logical structure classifying an entire multicastservice area;

FIG. 6 illustrates an example of an MBMS service stream identifier inaccordance with the present invention; and

FIG. 7 shows an example of setting the MBMS service stream identifier ina logical structure providing the multicast service of FIG. 5 inaccordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is implemented in a mobile communication systemsuch as the UMTS (universal mobile telecommunications system) developedby 3GPP. Nonetheless, the present invention can be also adopted for acommunication system operating in conformity to a different standard.Preferred embodiments of the present invention will now be described indetail.

The present invention proposes a method for discriminating a multicastservice so that different information can be provided by areas for oneservice or a service can be provided with different QoS by areas.

In addition, the present invention proposes a method for discriminatinga multicast service so that diverse menus or channels may exist for oneservice. For this purpose, in the present invention, a data identifiercan be attached to one multicast data stream. The data identifier mayinclude a multicast service identifier and an identifier indicative of akind of a corresponding multicast service. The identifier indicative ofa kind of the service may include a multicast group ID, a multicast areaID and an UDP/TCP port number, etc.

The selective service method in a multicast system in accordance with apreferred embodiment of the present invention will now be described indetail with reference to FIG. 4.

In general, when a multicast service is provided, there may be severaltypes of services related to one multicast group or there may be severalmulticast groups for one multicast service.

In the present invention, the entire multicast area is classified byservices, groups and RNCs. This classification can be defined by amember managing entity (i.e., SGSN, BM-SC and GGSN, etc.) of the corenetwork or in the UTRAN in the future. For example, the member managingentity of the core network can define a multicast service and a conceptof a multicast area providing the multicast service by using a logicalstructure as shown in FIG. 4.

FIG. 5 shows an example of three types of multicast services, that is,first to third services SER1˜SER3.

The service should be differently provided in accordance with each area.As shown in FIG. 5, the first service SER1 is provided in all multicastareas MA1-MA9. However, the second service SER2 is provided in onlymulticast areas MA1, MA2, MA4 and MA7 and the third service SER3 can beprovided in only multicast areas MA3, MA5, MA6, MA8 and MA9.

Also, a multicast group may exist for each of the services SER1˜SER3.Namely, the first service SER1 is provided to both the multicast groupsA and B, the second service SER2 is provided only to the multicast groupA, while the third service SER3 is provided to the multicast group B.The multicast group A includes multicast areas of MA1, MA2, MA4 and MA7,while the multicast group B includes multicast groups of MA3, MA5, MA6AND MA9.

With such a logical structure, in spite of the same multicast service, aQoS and a transmission content (MBMS data) may differ according to themulticast group and the multicast area. Preferably, the multicast areasMA1˜MA9 are mapped geographically. For instance, in consideration of thegeographical area, the first RNC manages an area corresponding to themulticast areas MA1, MA4 and MA7, the second RNC manages an areacorresponding to the multicast areas MA2, MA5 and MA8, and the third RNCmanages an area corresponding to the multicast areas MA3, MA6 and MA9.

Accordingly, a terminal belonging to the multicast areas MA1, MA2, MA4and MA7 can be provided with the first service SER1 or second serviceSER2 by joining the multicast group A, while a terminal belonging to themulticast areas MA3, MA5, MA6A and MA9 can be provided with the secondservice SER2 or third service SER3 by joining the multicast group B.

When the classification to the entire multicast area is completed, themember managing entity of the core network attaches an identifier for anMBMS service and an identifier indicative of a kind of a lower serviceof the MBMS service to the MBMS service data stream to be transmitted(step S2). The identifier indicative of a kind of a lower service of theMBMS service signifies an identifier indicative of a multicast group, amulticast area and an UDP/TCP port number. Nonetheless, in the presentinvention, without being limited thereto, various identifiers forproviding the MBMS service can be attached to the MBMS service stream asnecessary.

Accordingly, in order to transmit and receiving the MBMS servicediscriminately, as shown in FIG. 6, MBMS stream identifier is defined asfollows.

First, an MBMS stream identifier is defined to transmit different MBMSdata by multicast groups for one service.

Usually, a service such as weather information should be provided withdifferent information by areas. In the present invention, in the case ofthe weather information service, the current weather information can bemulticast appropriately to each area depending on areas. For example, asshown in FIG. 5, the first service SER1 is provided to both multicastgroups A and B, and in this respect, if the service subject is weatherinformation, different weather information can be transmitted to each ofthe multicast groups A and B. Accordingly, in order to transmit weatherinformation by discriminating the MBMS service, in the presentinvention, the MBMS service stream identifier can be defined by thebelow formula (1):MBMS service identifier=MBMS service ID+multicast group ID  (1)

The MBMS service identifier defined in formula (1) is used to providedifferent MBMS service data by multicast groups for one multicastservice or to provide the same data but with different QoSs by multicastgroups for one service. The MBMS service identifier can be defined inthe member managing entity (i.e., SGSN, BM-SC, GGSN, etc.) of the corenetwork or can be defined in the UTRAN in the future.

FIG. 7 shows an example of transmitting MBMS service data by multicastgroups by using the MBMS service identifier defined in formula (1).

With reference to FIG. 7, if the MBMS service data for the first serviceSER1 is transmitted to the multicast areas MA1, MA2, MA4 and MA7belonging to the multicast group A, a MBMS service ID is set to ‘1’ anda multicast group ID is set to ‘A’. If an MBMS service data istransmitted to the multicast areas MA3, MA5, MA6 and MA9 belonging tothe multicast group B, an MBMS service ID is set to ‘1’ and a multicastgroup ID is set to ‘B’.

Second, in the present invention, in order to transmit different MBMSdata by multicast areas for one service, an MBMS stream identifier isdefined by the below formula (2):MBMS service identifier=MBMS service ID+multicast group ID+Multicastarea ID  (2)

The MBMS service identifier defined in formula (2) is used to transmitdifferent MBMS service data by multicast areas for one multicast serviceor to provide the same data but different QoSs by multicast areas forone multicast service.

If the MBMS service data for the first service SER1 is transmitted tothe multicast area MA1 belonging to the multicast group A by using theMBMS service identifier defined in formula (2), the MBMS service ID isset to 1, multicast group ID is set to ‘A’ and multicast area ID is setto 1. Meanwhile, If the MBMS service data is transmitted to themulticast area MA4 belonging to the multicast group A by using the MBMSservice identifier defined in formula (2), an MBMS service ID is set to1, a multicast group ID is set to ‘A’ and a multicast area ID is set to4.

MBMS service identifiers can be set for the multicast areas MA2 and MA7belonging to the multicast group A and the multicast areas MA3, MA5,MA6, MA8 and MA9 belonging to the multicast group B in the same manner.

Third, in the present invention, an MBMS stream identifier can bedefined to provide diverse menus or channels for one multicast serviceprovided in the same area.

Currently, a multicast service provided from the same service, forexample, a paid TV service, provides various menus and channels. Withsuch a multicast service, even if users have requested the same servicein the same area, they may want different content of information. Thus,in order to meet their demand, it is necessary to provide a variety ofchannels so that they can select for their taste. Therefore, in thepresent invention, in order to provide diverse menus or channels for onemulticast service provided in the same area, an MBMS service streamidentifier is defined by the below formula (3):MBMS service identifier=MBMS service ID+multicast group ID+UDP/TCP portnumber  (3)

In case where the MBMS service identifier defined in formula (3) isused, if a user terminal belonging to the multicast area MA1 uses asub-menu 2of the first service SER1, an MBMS service ID is set to ‘1’, amulticast group ID is set to ‘A’, and UDP/TCP port number is set to1000. Meanwhile, if a user terminal belonging to the multicast area MA2uses a sub-menu 3 of the first service SER1, an MBMS service ID is setto ‘1’, a multicast group ID is set to ‘A’ and an UDP/TCP port number isset to 2000.

If a user belonging to other multicast area uses a sub-menu of aspecific service, the MBMS service stream identifier can be set in thesame manner.

Accordingly, a form of the MBMS service stream identifier including allthe three methods can be expressed in the below formula (4):MBMS service identifier=MBMS service ID+multicast group ID+[multicastarea ID]+[UDP/TCP port number]  (4)

The multicast area IDA and the UDP/TCP port number in the brackets arenot requisite but can be used as necessary. That is, in the presentinvention, in order to discriminate the MBMS service stream, the MBMSservice stream includes the MBMS service ID and the multicast group ID.The MBMS service ID may be represented by including, for example, anaccess point number (APN) and an IP multicast address.

Namely, the multicast area ID is additionally used in order to transmitdifferent MBMS service stream by multicast areas for one service or inorder to provide the same data but with different QoSs by multicastareas.

The UDP/TCP port number can be additionally used in order to providediverse menus or channels for one multicast service provided in the samearea.

Once the identifier for the MBMS service is attached to the MBMS datastream, the member managing entity of the core network multicasts acorresponding MBMS data stream to a terminal, and thereafter, when theMBMS data streams are completely transmitted, the process is terminated.If, however, there remain MBMS data streams to be transmitted, theoperation after the step S2 is repeatedly performed.

Accordingly, the terminal belonging to a specific group or a specificarea can selectively receive the MBMS data on the basis of the MBMS datastream multicast from the member managing entity of the core network.

As so far described, the selective service method of a multicast systemin accordance with the present invention have the following advantages.

That is, the multicast service stream identifier is provided so thateach multicast area can receive different information for one service orone multicast service can be provided with different QoSs to areas.

In addition, the multicast service stream identifier is provided bywhich a user can selectively receive diverse menus or channels for onemulticast service provided in the same area. Thus, by providing themulticast service stream identifier, users' desires for various servicescan be satisfied.

The foregoing embodiments and advantages are merely exemplary and arenot to be construed as limiting the present invention. The presentteaching can be readily applied to other types of apparatuses. Thedescription of the present invention is intended to be illustrative, andnot to limit the scope of the claims. Many alternatives, modifications,and variations will be apparent to those skilled in the art. In theclaims, means-plus-function clauses are intended to cover the structuredescribed herein as performing the recited function and not onlystructural equivalents but also equivalent structures.

1. A selective service method of a multicast system in a systemproviding a multimedia broadcast/multicast service (MBMS), comprising:attaching a service stream identifier (ID) to an MBMS data; andmulticasting the identifier-attached MBMS data stream.
 2. The method ofclaim 1, wherein the identifier comprises: an MBMS service ID; and an IDindicative of a kind of a lower service of the MBMS service.
 3. Themethod of claim 2, wherein the MBMS service ID consists of an accesspoint number (APN) and an IP multicast address.
 4. The method of claim2, wherein the ID indicative of a kind of a lower service is a multicastgroup ID.
 5. The method of claim 3, wherein the ID indicative of a kindof a lower service includes a multicast group ID and a multicast areaID.
 6. The method of claim 3, wherein the ID indicative of a kind of alower service includes a multicast group ID, a multicast area ID and anUDP/TCP port number.
 7. A selective service method of a multicast systemin a system providing a multimedia broadcast/multicast service (MBMS),comprising: attaching a first identifier (ID) for an MBMS data multicastservice; attaching a second identifier indicative of a kind of a lowerservice of an MBMS data; and multicasting the MBMS data stream with thefirst and second identifier attached thereto.
 8. The method of claim 7,wherein the first identifier is an MBMS service ID.
 9. The method ofclaim 7, wherein the MBMS service ID consists of an access point number(APN) and an IP multicast address.
 10. The method of claim 7, whereinthe second identifier is a multicast group ID.
 11. The method of claim7, wherein the second identifier includes a multicast group ID and amulticast area ID.
 12. The method of claim 7, wherein the secondidentifier comprises: a multicast group ID; a multicast area ID; and anUDP/TCP port number.
 13. A selective service method of a multicastsystem in a system providing a multimedia broadcast/multicast service(MBMS), comprising: classifying an entire multicast service area intocertain units; attaching an identifier of the classified area to amulticast data stream and transmitting it.
 14. The method of claim 13,wherein the entire multicast area is classified by multicast groups, bymulticast areas and by multicast services.
 15. The method of claim 13,wherein the identifier is performed by a member managing entity of acore network.
 16. The method of claim 15, wherein the member managingentity is one of a Broadcast Multicast-Service Center (BM-SC), a ServingGPRS Support Node (SGSN) and a Gate GPRS (GGSN).
 17. The method of claim13, wherein the identifier is an MBMS service IDA and a multicast groupID.
 18. The method of claim 17, wherein the MBMS service ID consists ofan access point number (APN) and an IP multicast address.
 19. The methodof claim 13, wherein the identifier includes: an MBMS service ID; amulticast group ID; and a multicast area ID.
 20. The method of claim 13further comprising: attaching another identifier indicative of a kind ofa lower service to the multicast data stream.
 21. The method of claim20, wherein the identifier indicative of a kind of a lower service is anUDP/TCP port number.